


Testing a Theory

by magentastorm



Category: Lucifer (TV)
Genre: Blow Jobs, Humor, M/M, Seduction
Language: English
Status: In-Progress
Published: 2016-09-12
Updated: 2016-10-07
Packaged: 2018-08-14 14:19:38
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 1,641
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8017306
Author URL: https://archiveofourown.org/users/magentastorm/pseuds/magentastorm
Summary: <blockquote class="userstuff">
              <p>Set around/after 1x05. </p>
<p>Lucifer wants to test if it's only Chloe who's immune to his charms. Dan is a convenient test subject.</p>
            </blockquote>





	1. Chapter 1

"Shit, you're actually serious, aren't you?"

"Of course."

"You're actually, seriously trying to get me to have sex with you?" Dan asked again.

"You sound like a broken record. Yes. That's what I've been saying for the past five minutes."

Dan pinched the bridge of his nose. He could feel a headache forming. "You're insane. Like, genuinely certifiable."

"Many would argue that turning down the best sex of your life is insanity."

Dan had no idea how the hell he'd even gotten into this conversation. He'd been getting closing statements from Lucifer on a case Chloe had just cracked, when Lucifer had suddenly turned to him him with a manic glint in his eye and started raving on about mortality and magic powers or something Dan wasn't remotely prepared to listen to. And then he'd propositioned him, as casually as one might ask for the time.

"'Let me get this straight. You're trying to seduce me to find out if your magical seduction powers are broken?"

"Yes!" Lucifer sighed theatrically, as though _Dan_ were the one being unreasonable.

"As I've already explained, I'm trying to find out exactly how I'm being affected by this whole 'turning mortal' thing. For a start, I need to see if it's just Detective Decker that's immune." He said in a tone one would use when explaining something to a small child.

"And... you think _I'm_ the best candidate for this test?"

"Well, obviously it can't be someone too easy. And you're the most convenient because you're here right now. Lucky you." Lucifer said, grinning like a shark.

Dan laughed incredulously. "I can't believe I actually have to say this, but I am not going to sleep with you, Lucifer."

"Mmm. We'll see. I haven't actually tried yet." Lucifer waved his hand dismissively.

"Does it occur to you that my turning you down might not have anything to do with your "powers," - he couldn't physically bring himself to say the word without air quotes - "and more to do with my being-"

"Straight?" Lucifer rolled his eyes, and groaned as if the word physically pained him. "Contrary to popular belief, true Kinsey 0's are uncommon. Statistically, it's not likely that you're one of them, so that shouldn't be a problem. Anyway, rest assured you would be far from the first "straight" man I've bedded-"

"Right," Dan cut in. "I've had about as much as I can take of this weirdness."

He turned to leave, but Lucifer grabbed his arm and stepped closer.

"Are you sure you're not interested? Not even a little bit?"

Suddenly, it was like a magnet was holding his eyes to Lucifer's. 

"Uh...I..." he stammered, feeling like the temperature had gone up ten degrees and all the air had been sucked out of the room.

Lucifer grinned triumphantly, which was a truly terrifying sight. Dan backed away a few steps, trying to will himself to look away. He was forced to stop when his back hit the bar. Lucifer leaned forward. Their bodies weren't quite touching, but he could feel the warmth, and smell some very expensive cologne. 

"Don't do that... that... _whatever_ you're doing. It's cheating!" He protested weakly.

"It wouldn't work if you weren't already interested," Lucifer insisted. "I only have the power to make people admit to their buried desires, not manufacture false ones."

Dan heard this dimly through the hazy feeling that Lucifer seemed to be casting over him. The next moment he managed to pull his gaze away, and the tension abruptly released like a wire snapping.

"I'm quite sure I'm not interested," he said, voice only shaking a little. "Sorry to disappoint."

"Oh, I assure you, it is entirely your loss. The Devil doesn't have a gag reflex."

Lucifer smirked and turned on his heel and strode away, leaving Dan standing by the bar floundering in utter disbelief.


	2. Chapter 2

Dan had firmly made up his mind to forget about the whole thing and pretend it never happened. Actually doing that, however, soon proved to be much harder than he'd thought. Now that Lucifer had put the idea in Dan's head, like the proverbial pink elephants, it was near impossible to get out.

The next day he found himself wondering what would have happened if he had taken Lucifer up on his offer. Just idly at first, a passing thought with no true consideration. But by evening it had grown more pervasive, niggling at the back of his mind. By the end of the week the situation was becoming unbearable. Far from fading away with time, the curiosity only got stronger. The next morning he woke up with sticky sheets and the lingering image of Lucifer's wicked mouth around his cock.

Okay, he could have dealt with that, embarrassing as it was, if it weren't for the fact that he couldn't concentrate properly at work, or anywhere else. It really didn't help when his next case forced him into Lucifer's path, whereupon the _absolute bastard_ spent half his time standing unnecessarily close and making suggestive comments that not-so-subtly implied that his offer was still very much open.

And God help him, Dan found he was actually considering it. Fuck.

By the time the murderer had been arrested - after a dramatic shoot-out at Lux, because _of course_ Lucifer was always the centre of the universe - Dan had reached breaking point. Giving in was the only way, he reasoned. He couldn't spend the rest of his life willing away semis at inappropriate times. Just once. Just once to get whatever the fuck this was out of his system and then he could move on with his life.

Dan found excuses to linger until he was the last officer left in the building. As soon as the door shut behind the last of his colleagues, Lucifer turned to him, grinning widely.

"I see you've had a change of heart, Detective."

"What makes you think that's why I'm here?" Dan snapped. "I could have further questions about the case."

"But you don't, do you?"

Dan gritted his teeth. "No."

"Lovely." Lucifer purred. 'Shall we take this upstairs?"

**Notes for the Chapter:**

> Last (smutty) chapter is half-written. Hopefully it'll be finished within a week or two.


	3. Chapter 3

As soon as they stepped into the elevator, Lucifer pushed him against the wall and kissed him. Against all good judgement, Dan found himself responding. He grabbed Lucifer's shoulders and kissed back. Lucifer's tongue swept into his mouth and his thigh slipped between Dan's, pressing against his rapidly hardening dick. He arched against him with a groan.

When the doors opened, Lucifer left him as suddenly as he'd pounced on him, heading swiftly towards the bedroom. Dan stumbled after him, feeling slightly dazed. His skin was flushed and his lips were tingling. He licked them, and tried to calm his breathing, which wasn't easy with Lucifer eyeing him like a hungry wolf. He paused in the doorway, hardly able to believe that this was really happening. He shouldn't be doing this, he _really_ shouldn't be doing this. But God he wanted to. It had been ages since he'd felt someone else's touch - not since he and Chloe had split and _fuck, don't think about her now, this is weird enough._

Lucifer swooped - yes, fucking _swooped_ was the best word to describe it - back over to him. He leaned in close, lips brushing his ear as he murmured "Just relax and enjoy it. Stop thinking."

His proximity and that damn voice sent shivers through Dan. With a frustrated noise at how much Lucifer was affecting him, Dan captured his mouth in a rough kiss. Lucifer gave as good as he got, pressing him against the wall and _devouring_ him, all tongue and teeth. Head spinning, Dan had to pull away to catch his breath. So much for trying to get the upper hand. The next thing he knew, Lucifer had undone his belt and pants and was reaching inside. Dan moaned and thrust into his hand. He should have been embarrassed by how eager he was but he found he couldn't care less at the moment. Especially when Lucifer dropped to his knees.

Dan's cock throbbed, getting even harder as Lucifer's mouth closed around him. There was no teasing. He immediately established an even rhythm, sucking strongly, tongue doing something impossibly amazing. Dan clutched at the door-frame to stay upright and tried to focus on not embarrassing himself by coming faster than he had since he was a teenager.

True to his word, Lucifer could - and did - take his entire length down his throat effortlessly. Tight, silky heat fluttered around the head as he swallowed around him. Dan made a noise that could only be described as a whimper and his hips jerked forward of their own accord.

"Sorry, sorry," he panted.

Lucifer pulled back and, not even sounding the slightest bit out of breath, said "Not at all. Go for it. Fuck my mouth."

Dan nearly came at those words, biting his tongue to hold himself back. He took a few deep breaths and slid his cock back into Lucifer's willing mouth, not stopping until he hit the back of his throat. He moved slowly at first, until Lucifer grabbed his hip, urging him to be less careful. He twined his fingers through his hair, pulling a little as he thrust harder. Lucifer moaned around him with enthusiasm, like he was getting off on this just as much as Dan was.

He looked just like he'd imagined it, lips red and swollen and wet, dark eyes flashing. Dan drank in the sight until he felt himself getting close to the edge again. He squeezed his eyes shut and his head fell back against the wall with a groan. He slowed down a little, trying to hold on to this glorious feeling as long as he could, until finally it was too much. He managed to gasp a warning before his vision whited out as he came.

**Notes for the Chapter:**

> This was going to be the end but I ended up starting to write a bit more. To keep the chapters a bit even-ish I've posted this bit now and I'll finish the rest soon-ish.


End file.
